1. Field of the Invention
This invention relates to a substrate processing apparatus supplying a raw material such as antimony oxide (Sb2O3) etc. in a sublimated state to a substrate such as a semiconductor substrate, and a manufacturing method of a semiconductor device.
2. Description of the Related Art
FIG. 7 is a schematic sectional view of a conventional processing apparatus of a substrate. As shown in the Figure, a heater 2 is prepared outside the outer tube 1, an inner tube 3 is prepared inside the outer tube 1, a cap 4 that can be lifted and lowered is inserted in the inner tube 3, a boat 5 is mounted on the cap 4, and a plurality of semiconductor substrates (not shown in the figure) are supported on the boat 5. A raw material sublimating apparatus 6 is prepared outside the outer tube 1 and the inner tube 3, that is outside the reactor, one end of a raw material introducing tube 7 is connected to the raw material sublimating apparatus, the other end of the raw material introducing tube 7 is located in the upper portion of the inner tube 3, and the raw material introducing tube 7 is communicating with the inside of the inner tube 3. An exhaust tube 8 is prepared in the lower portion of the inner tube 3.
In this substrate processing apparatus, when antimony oxide is put in the raw material sublimating apparatus 6 and heated, while the semiconductor substrate supported on the boat 5 is heated by the heater 2, antimony oxide sublimates, the vapor of antimony oxide is supplied through the raw material introducing tube 7 to a surface of the semiconductor substrate, and antimony oxide is diffused into the semiconductor substrate. A exhaust gas is cooled by the cap 4, and exhausted through an exhaust tube 8.
FIG. 8 is a schematic sectional view of the other conventional substrate processing apparatus described in Japanese Patent Application Laid-open HEI06-28248, and FIG. 9 is an enlarged A—A sectional view of FIG. 8. As shown in Figures, a subreactor core tube 12 is connected with the main reactor core tube 11, a main reactor core tube heater 13 is prepared outside the main reactor core tube 11, a subreactor core tube heater 14 is prepared outside the subreactor core tube 12, a soaking tube 15 is prepared between the subreactor core tube 12 and the subreactor core tube heater 14, a semiconductor substrate 16 is mounted inside the main reactor core tube 11, and an impurity boat 17 is prepared inside the subreactor core tube 12.
In this substrate processing apparatus, when antimony oxide powder is heated by the subreactor core tube heater 14 after mounting antimony oxide powder on the impurity boat 17, while heating the semiconductor substrate 16 by the main reactor core tube heater 11, antimony oxide is sublimated, the vapor of antimony oxide is supplied to a surface of the semiconductor substrate 16, and antimony oxide is diffused into the semiconductor substrate 16.
In the substrate processing apparatus shown in FIG. 7, however, the raw material introducing tube 7 is connected with the raw material sublimation tube 6 via a sealant such as an O-ring in order to maintain the airtightness of the connecting portion, however, by no means the temperature in the vicinity of the successive portion is lower than the sublimating temperature of the raw material, since the circumference of the O-ring is cooled due to the low heat-resistance of the O-ring (usually, approximately 100 to 300° C.). As a result the temperature of the connecting portion becomes low, and antimony oxide re-solidifies at this portion and attaches to the inner surface of the inner tube as reaction products. Thus cases may arise in which the vapor of antimony oxide cannot be supplied to the surface of the semiconductor device.
In the substrate processing apparatus shown in FIGS. 8 and 9, the raw material antimony oxide is heated and sublimated by the subreactor core tube heater 14 placed outside the subreactor core tube 12, however, there is a possibility that the control of sublimation becomes poor, because the raw material and the heater 14 are prepared in a separate manner as a result of the heater 14 being placed outside the reactor, and because a multiplicity of interventions such as the subreactor core tube 12 and the soaking tube 15 placed between the raw material and the heater 14 influence the temperature.
In the conventional apparatus shown in FIGS. 8 and 9, which is a so-called horizontal type apparatus, in which a rector core tube is located in the horizontal direction, it is only necessary to consider the plane area of the clean room where the apparatus is installed, even when the main reactor core tube 11 and the subreactor core tube 12 are separated (i.e. even the length of reactor core tube is long) so that the temperature of the reactor is not influenced and as is the case of the conventional apparatus shown in FIG. 7, the main reactor core tube 11 on which the substrate is mounted and the raw material sublimation space can be communicated, even when the connection portion using an O-ring is not prepared. However, in the case of the vertical type apparatus (i.e. the reaction tube is located in the vertical direction) shown in FIG. 7, which is the mainstream of the production line for a semiconductor device, it was not possible to simply increase the length of the reactor core tube in the vertical direction due to the limitation of the height of the clean room where the apparatus is installed.